\subsection{XML Import}
To import the xml document "mondial" we make use of "simplexml_load_file" function to load the document in as a big object. On this object we can then for each node, such as continent, country and city, select each of their properties and query them into the database. We chose to only extract a subset of the XML document as this subset give plenty of experience with how to set up and use a MVC design with a database. So for continents we extract; ID and the name, for countries we extract; ID, name, population, car code, capital city and the ID of the continent it belongs to, for cities we extract; ID, name, population and the ID of the country it belongs to. 

In our original design of our database we chose to use "int" for the IDs of the continents, countries and cities, but the XML document we imported data from used "string". So we had to make changes to our database and our MVC design so it make use of "string" instead.
Other problems we encountered was that not all cities had a population, this gave us an error. So when a city return nothing we simply set it to 0.